In a Device-to-Device (D2D) communication system, when a service between the User Equipment (UE) is required to be transmitted, service data between the UEs is not forwarded by the base station, but is transmitted directly from the data source UE to the target UE via an air interface as shown in FIG. 1. FIG. 1 is a structure block diagram of the D2D communication in the related art. This communication mode has the characteristics distinct from a conventional cellular system communication mode. For near field communication users who can use the D2D communication mode, D2D transmission not only saves the wireless spectrum resources, but also reduces the data transmission pressure of the core network. The D2D transmission can reduce the system resource occupancy, increase the spectral efficiency of the cellular communication system, reduce the terminal transmission power consumption, and save network operation costs to a large extent.
In a conventional cellular communication system, the radio resources of the UE are controlled and scheduled uniformly by the evolved NodeB (eNB). The eNB indicates the UE of configured downlink or uplink resources by the Physical Downlink Control Channel (PDCCH). The UE receives data signals transmitted by the eNB on the corresponding downlink resource according to the eNB configuration indication or transmits signals to the eNB on the uplink resource.
In a Long-Term Evolution (LTE) system, the radio resource is divided in units of radio frames in the time domain. Each radio frame is 10 ms and contains 10 subframes. Each subframe is 1 ms and is divided into two slots of 0.5 ms, as shown in FIG. 2, which is a structure block diagram of the LTE system frame in the related art.
In cellular communication, an eNB schedules and indicates, to UE, on the PDCCH resource of the downlink subframe #n, the Physical Downlink Shared Channel (PDSCH) resource configured in the current subframe. FIG. 3 is an indication diagram of the LTE system resource scheduling in the related art. The UE receives the indication information in the PDCCH, and receives the Transport Block (TB) on the corresponding Resource Block (RB) in the subframe #n according to the indication information to obtain the data transmitted by the eNB, as shown in FIG. 3. FIG. 4 is an indication diagram of the D2D communication resource scheduling in the related art. In the D2D communication system, data is directly transmitted between the UEs. The transmitter UE needs to transmit the D2D control information and indicates, to the receiver UE, the resources and other related information used by the transmitted data signal. Due to the particularity of D2D communication, the transmitter UE transmits D2D data according to the scheduling of eNB or by selecting one or more Physical Sidelink Shared Channel (PSSCH) in an valid resource pool, and indicates the used PSSCH subframe and the associated control information in the D2D link (also referred to as Sidelink) Control Information (Sidelink Control Information (SCI)) signaling. The bitmap sequence corresponding to the PSSCH subframe configuration is indicated by a Time Resource Pattern (TRP) information. The bit labelled as “1” in the indicated bitmap sequence indicates that the corresponding subframe is a PSSCH subframe. The bitmap sequence is used for mapping circularly in the cycle to achieve the configuration indication of the PSSCH subframe during the entire cycle. Due to the fixed bitmap sequence length and the limited TRP indication overhead, the flexibility of the D2D PSSCH subframe configuration is limited.
There is no valid solution for low flexibility of the D2D PSSCH subframe configuration in the related art.